Safety device



Oct. 27, 1931. .1. J. EHEMANN. sR.. ET AL 1,329,473

SAFETY DEVICE Filed March 23, 1929 2 Sheets-Sheet 1 JJE/zemann, 57:

B. if Jz'no'er /%69 WWW Oct. 27, 1931.

J. J. EHEMANN, SR ET AL SAFETY DEVI CE Filed March 23, 1929 2 Sheets-Sheet 2 Elnucnfoz J Jflkemann, J2?

Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE I JOSEPH J. EHEMANN, SR, AND BENJAIMIN F. SING-ER, OF LANCASTER, PENNSYLVANIA SAFETY DEVICE Application filed. March 23, 1929. Serial No. 349,474.

This invention is a safety device for use upon automobiles and its object is to provide a device which will automatically arrest the movement of the vehicle if it should start to 5 travel backward on a down grade. It is the habit with motorists to take all grades in high gear to avoid the labor of shifting gears and it frequently happens that the machine stalls before the top of the hill has been reached and, unless the chauffeur is adept at shifting gears, the machine will travel backward some little distance before its progress can be stopped. Numerous bad accidents have occurred through the lack of means to instantly stop the rearward travel of the machine, and the object of the present invention specifically stated is to provide means which will automatically operate to prevent reverse travel of the vehicle on a down grade. The invention provides means whereby when the reverse travel of the machine is desired the safety device will be thrown into inoperative position and will then not interfere with the desired travel until the gears have been shifted to again provide for forward travel. The invention is illustrated in the accompanying drawings and will be hereinafter first fully described and then more particularly defined in the appended claims.

In the accompanying drawings:

Figure 1 is a sectional elevation of the transmission gearing of an automobile and the cooperating parts showing our present invention embodied therein.

Fig. 2 is an enlarged longitudinal section through the safety device,

Figs. 3 and 4 are elevations showing operative and inoperative positions of the device, and

Fig. 5 is an enlarged detail perspective view of the hub.

In the drawings, the reference numeral 1 indicates a portion of the motor housing, 2 indicates the transmission gear housing and 3 the usual hand lever controlling the transmission gearing through shifting rods 4 and selector yokes 5. In carrying out the present invention, there is provided a circular case 6 which is secured rigidly to the rear end of the transmission case around the propeller shaft 7. Keyed to the shaft within the case 6 is a hub 8 which is constructed with a plurality of right angular recesses 9 in its periphery, each of which forms with the annular wall of the case 6 a triangular chamber 10. Disposed within each chamber 10 is a free roller 11 and in the base wall of the right angle is formed a socket 12 receiving a pin 13 which carries a cup 14 at its free end, anexpansion spring 15 being disposed around the pin 13 between the base wall 16 and the cup, as shown in Figs. 3 and 4. The cup is adapted to fit close to and press upon the roller 11 so that the spring 15 tends constantly to hold the roller at the point of the triangular charm ber 11 and thereby causes the roller to bind between the walls of the chamber and prevent movement of the shaft 7 in one direction. Disposed at the side of the'hub are a plurality of cranks 17 each of which carries a fulcrum pin 18 engaged in a socket 119 formed in the hub whereby the crank may rock in the operation of the device. The crank projects over the triangular chamber 10 and at its projecting end is equipped with a pin 19 which is adapted to bear upon the roller 11 in opposition to the cup or presser plate 14 and hold the roller in an inoperative position. At the inner end of the crank is a lug 20 which is adapted to be engaged by the tapered end 21 of a sleeve 22 so that the crank may be rocked and the roller permitted to move to the point of the triangular chamber. The sleeve 22 is provided with an annular groove 23 in its outer end which is engaged by the selector yoke 5 on the shifting rod 4 which controls the reverse gear and normally 'the sleeve is away from the several lugs 20,

as shown in Figs. 1 and 2. To accommodate the several cranks 17 lugs 24 are provided upon the side of the hub 8 and a cap ring 25 is secured upon the case 6 and rests upon these lugs and projects over the several cranks and the rollers to prevent loss of the same.

Ordinarily, when the shaft 7 is rotating to drive the vehicle forward, the speed thereof, through centrifugal action will cause the outer ends of the cranks 17 to swin about their respective pivots 18 and overcome the force of thesprings 15 so that the rollers 11 will be held in retracted position, as shown in Fig. 4. In this position the rollers will the rearward travel. 7

Having thus described the invention, we

be out of contact with at least one wall of the triangular chambers and the forward rotation of theshaft may c'ontinuevwithout interruption Even if the speed should be insuflicient to rock the vcranks 'as'st'a ted, the millers w'ou'ldfail 'to bind. The forward m0vefment of the shaft carries the apexes 'of'the' triangular r'chambers in a, direction;aw:ay from therollers so that the resistance to the movement of the rollers is removed but re 'verse movement of the shaft carries the points of the respective chambers 11 and, consequently, will bind between the side walls thereof an-d prevent"backward rotation. of the shaft. If it be desired to have themachine travel rearwardly; the reverse gear is thrown inin the usual manner and this action fcauses the sleeve 21 to slide into engagement w th the several lugs 20 and bear against the convex inclined surfacesofthe sameand rock the cranks so that the rollers will be positively held in their retracted positions, as will be understood upon reference to Fig. 4.

stationary case, a hub rotatable concentrically within the case and having a right angular recess in its periphery forming with the wall of the case a triangular chamber, a roller freely disposed within said chamber, a pin slidably mounted in the base wall of the right angular recess at a right angletp the axis of therdllerfapre sser plate earriedby the pin and having a" concave face to engage the rollery'an expansion spring acting on the presser plate and disposed 'betweenthe g iame and the basal wall, a crank pivotally mounted fan end of the hub, a pin extending from the outer end of the crank into the rece'ss parttllelwitlfithe axis of the roller at the side thereof opposite the presser plate, alug on the inner endpf t'he crankprojectingtherefrom in a direction a'wa y'trom the end 'oftfhe hub and means toeni a-e said 1 1a forrock J i O ing the crank whereby'to hold thero'ller inh opposition'to the pre'sser'plat'e; V

In testimony whereof we aflix our signa- Q1 W JOSEPH J. S'R. BENJAMIN F; SINGER.

From the foregoingdescription, taken in connection with the accompanying'drawings, twillbe seen that We have provided a Very simple and compact device which maybe readily applied to existing automobiles or installed invehiclesnow building. The or- 'clinary operation of the automobile will not be affected by the safety device but any attempt of the machine to travel bac'kwardly, V

as upon a steep grade which it is desired to ascend,wvill cause the brake rollers to 'automatically shift into lockingposition and stop claim; v 4 1. In a safety device, the combination of a stationary case,a hub rotatable within the casea'nd having a tapered recess in its periphery, a' roller disposed freely in said'recess a 'yieldably mounted presser plate carried thehub and engaging the roller to hold the I same in engagement with the walls of the re- [eessand the case'to prevent reverse movement of the hub; a crank pivoted between its ends onfan end of the hub, a pin carried by the outer end of the crank andextendin'g within the recess parallel with the axis of the roller; the roller being between the presser and the pin and means acting on the inner end cfthe crankto rock the same wherebyto overcome the presser and permit reverse movement of the hub.

In a jsafety device the combination OfJa 

